Enzymatic composition of canine leg lymph

In an experimental study employing anaesthetised dogs, lymph from the deep lymphatic system in a hind leg was sampled at 15-min intervals. Lymph and corresponding plasma samples were analysed for ten different enzymes and for protein. In a control group a preliminary period of 15-min lymph collections was followed by 1 h of 'rest' (no passive movement of leg) and restoration of the lymph flow for another 2 h. In a hypoxic group during the 1 h of 'rest' the blood supply of a hind limb was interrupted to cause an increase of enzyme release. Neither lymphatic enzyme activity nor lymphatic transport of enzymes was increased by hypoxia. Enzyme activities in plasma did not show any elevation either. From lymph plasma quotients of enzymes and protein it is deduced that cellular enzymes have to be transported into the intravascular space by lymph flow and scarcely via a direct entry across capillaries.